In the first part of this study the development of probation work is traced. It is shown that emphases from the past influence perceptions and aims of workers today. A new analysis of these is presented suggesting that workers' aims can be expressed on a continuum between two ORIENTATIONS, the JUDICIAL and the CLINICAL. In the second part of the study, after description of characteristics of worker and probationer samples, four hypotheses are tested. Firstly changes in the behaviour of probationers subsequent to the making of a probation order are measured not only, as is usual, using reconviction rates, but also utilizing undetected offending rates, changes in the numbers of convictions, in the number of undetected offences, in the seriousness of these, in social stability, in employment stability, in attitudes (to work, law and authority, probation and self) and in social functioning. Little change in the behaviour of probationers is found. Secondly, the outcome of probation in Scotland and England is compared. No consistent differences are found. Thirdly, the existence of ORIENTATIONS and the feasibility of expressing aims of probation workers on the continuum between JUDICIAL and CLINICAL ORIENTATIONS are examined. The concept of ORIENTATIONS receives support; the measurement method devised appears workable. Lastly, there is examination of changes in the behaviour of a subsample of probationers matched with their workers who were categorised using a tripartite division of the JUDICIAL/CLINICAL scale. Those probationers whose workers had a CLINICAL ORIENTATION appear to have fewer reconvictions and to have committed fewer undetected offences. Those probationers whose workers had an INTERMEDIATE ORIENTATION, that is, who fell in the middle of the scale, appear to have made greater change in a positive direction on all the other measures.